Field of the Disclosure
The present disclosure relates to a damping apparatus disposed on a machine tool for reducing vibration of a workpiece held by a spindle of the machine tool for machining.
Background of the Disclosure
Although its main purpose is not vibration reduction, there has been known a center rest that supports an elongated workpiece held by a spindle of a machine tool for machining to reduce run-out of the workpiece (see Japanese Unexamined Patent Application Publication No. 2000-317756 and Japanese Unexamined Patent Application Publication No. 2004-181587).
Both of the center rests disclosed in Japanese Unexamined Patent Application Publication No. 2000-317756 and Japanese Unexamined Patent Application Publication No. 2004-181587 have two sets of two rotating rollers, i.e., four rotating rollers in total, arranged symmetrically with respect to the spindle axis, and have a configuration in which a workpiece is sandwiched and held by the four rotating rollers. Each of the rotating rollers is held by an appropriate support body to be rotatable about an axis parallel to the spindle axis and is supported by the support body to be movable in directions toward and away from the spindle axis, and at least two of the rotating rollers are biased toward the workpiece by a spring body so that the workpiece is sandwiched and held between the rotating rollers and the other rotating rollers.
Thus, according to such a center rest, an elongated workpiece, which is held by a spindle at one end thereof, is held by the center rest at the other end thereof, whereby run-out of the other end of the workpiece is reduced.
Further, since such a center rest has a configuration in which the rotating rollers are biased toward the workpiece by a spring body, when vibration occurs on the workpiece during machining, the rotating rollers vibrate themselves in response to the vibration propagated thereto so as to absorb and consume energy of the vibration, thereby damping the vibration. Therefore, it is conceivable that this center rest is capable of reducing vibration of the workpiece to some extent.